AND THOSE OF CERTAIN OTHER MAMMALIA. 103 



it may be remarked that the halitus evolved on opening the great 

 cavities of each of these animals possesses a very similar odour. 

 Upon the first of these two points, perhaps, little stress should be 

 laid, as it may be either a result or a necessity of the mode of life 

 of either creature ; and the latter, depending entirely upon the 

 evidence of the sense of smell, has consequently but a subjective 

 cogency. Much greater importance should be assigned to the 

 statement, now ordinarily made 1 , to the effect that the Cetacea have 

 no azygos veins at all, as this peculiarity would, if it really did exist, 

 differentiate them from all other mammals whatever. But on 

 looking at the words of Von Baer 2 , upon whose authority this 

 statement is made, and at the facts with which Von Baer's words 

 are usually in accordance, it will be found that the vena-azygos 

 system not only does exist in Cetacea, but actually furnishes us 

 with an additional point of affinity between them and the large 

 ungulate Mammalia. Von Baer's words, in the 'Bulletin de 

 l'Academie Imperiale des Sciences de St. Petersbourg,' 1. c, are : 



' La veine dite impaire qui manque excepts le bout anUrieur, et dont les sinus de la 

 colonne verte'brale tiennent lieu.' 



This anterior end, however, is a very considerable vessel ; and in 

 the ' Nova Acta ' (1. c.) I find that Von Baer describes it as having 

 a trunk as large as that of the vena cava superior, which it joins ; 

 and he goes on to state that its large size is not to be accounted for 

 by its intercostal factors, but by the junction to it of a trunk from 

 within the vertebral canal, of large size and connected by its 

 constituent factors, as the vena azygos is, with those of the lower 

 cava as also with the lower intercostal veins. If we examine 

 a pig, we shall find it to possess a large azygos vein on the left 

 side ; and this the cetacean, it is true, does not ; but it will be seen 

 to have on the right side a short vena azygos, just as the porpoise 

 has, with four or five affluents from the upper intercostal spaces, 

 as well as very considerable tributaries from the muscles of the 

 back and scapulae. The vena-azygos system is well known to be 

 intimately connected with venous ramifications situated about, 

 around, between and within the spinal column ; and the greater 



1 'Phil. Trans.' for 1849, p. 152; Milne-Edwards' ' Physiologie Comp.' vol. iii. 

 pi. 2. p. 598. 



2 ' Nova Acta,' vol. xvii. pi. 1. p. 408, 1834 ; ' Bull. Acad. St. Petersbourg,' torn. i. 

 1835; Froriep, 'Notizen,' 50, p. 38, 1836. 



